Nip pressure sensing system

Abstract

A roll sensing system for measuring the pressure distribution and nip width in a nip roll press. The sensing system comprises a strip having sensors thereon, the strip being placed in a nip press, for sensing the pressure at several locations therealong. At one end of the strip lies electronics associated with the sensors. The electronics communicate with an optional multiplexer and a bidirectional transmitter for signal transmission to an external signal conditioner and an external computer. The computer determines pressure values and nip width values at various locations along the strip, and communicates with a display which provides a visual, graphical and/or numerical data to the operator. Optionally, a control system can be in communication with the transmitter or the computer to initiate crown corrections in response to pressure or nip width readings.

What is claimed is:  
     
       1. A system for measuring nip widths between two rolls in a nip press at a plurality of locations along the lengths of the rolls while the rolls are in a static condition, said system comprising: 
       a flexible, elongate strip adapted to be placed in said nip press;  
       a plurality of separate, spaced apart sensors disposed along the length of said strip for providing signals representative of the nip width between said two nip rolls at the plurality of locations;  
       each of said sensors having an effective sensing length greater than the expected nip width whereby said sensor may be stationarily positioned such that said effective sensing length extends entirely across the nip width and being configured such that, when said sensor is stationarily positioned between the two nip rolls with at least a portion of said sensor positioned within the nip width, said sensor is operative to respond to pressure exerted thereon by the two nip rolls by providing a signal proportional to the area of said sensor under pressure; and  
       a computer for accessing said signals and calculating values representative of said signals.  
     
     
       2. The system according to  claim 1 , said system further comprising a display, coupled to said computer, for providing a visual representation of said values. 
     
     
       3. The system according to  claim 1 , wherein said computer is adapted to perform measurements of nip width from said signals. 
     
     
       4. The system according to  claim 1 , wherein said computer is adapted to automatically request measurements of nip width at predetermined times. 
     
     
       5. The system according to  claim 1 , said system further comprising a wireless transmitter for communicating said signals to said computer. 
     
     
       6. The system according to  claim 1 , said system further comprising a control system in communication with said sensors for initiating corrective measures to said nip press. 
     
     
       7. A method for measuring nip widths in a nip press comprising first and second rolls at a plurality of locations along the lengths of the rolls while the rolls are in a static condition, said method comprising the steps of: 
       providing a flexible elongate strip and a plurality of sensors disposed along the length of said strip for providing signals representative of nip width between said first and second rolls, each of the sensors having an effective sensing length greater than the expected nip width and being configured such that, when the sensor is stationarily positioned between the two nip rolls with at least a portion of the sensor positioned within the nip width, the sensor is operative to respond to pressure exerted thereon by the two nip rolls by providing a signal proportional to the area of the sensor under pressure;  
       positioning the strip between the two nip rolls as they are stationary with at least a portion of the sensor positioned within the nip width and such that the effective sensing length extends entirely across the nip width;  
       while the sensors are stationarily positioned with respect to the nip width and the effective sensing length extends entirely across the nip width, generating signals with the sensors which are proportional to the areas of the sensors under pressure;  
       computing measurements from said signals with a computer in communication with said sensors; and  
       displaying said measurements on a display coupled to said computer.  
     
     
       8. A method according to  claim 7 , said method further comprising displaying locations along the strip where the nip width is being sensed. 
     
     
       9. A method according to  claim 7 , said method further comprising displaying the nip width of said nip press. 
     
     
       10. A method according to  claim 7 , wherein said positioning step comprises positioning said strip against said first roll and loading said second roll against said first roll.